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STORY: Riot police cleared Tahrir square after clashes went on for several hours with protesters.
Tens of civilians were seen on the riot police's side aiding them fight off protesters in Tahrir square.
Security forces in Cairo fired tear gas on Tuesday to disperse protesters, as clashes erupted between supporters of Egyptian military General Abdel Fatah al-Sisi, and crowds gathered to commemorate bloody clashes two years ago that left 42 dead.
The protests were a mark of the turmoil that has dogged Egypt since the army ousted elected Islamist President Mohamed Mursi in July and took back control of the Arab world's most populous state.
Protests by Egyptians opposed both to military-dominated rule and Mursi's Muslim Brotherhood movement began in downtown Cairo on Monday night.
Since the military removed Mursi, the country's first democratically elected president in early July, army chief Sisi has become a wildly popular figure in Egypt with state media whipping up public sentiment against the Brotherhood.
But a small minority of hardcore activists from the 2011 uprising, that toppled long-time president Hosni Mubarak, are questioning this official narrative.
They are using the anniversary of the November 2011 clashes on Mohamed Mahmoud Street to draw attention to the actions of security forces, who have acted mostly with impunity in nearly three years of political upheaval.
Security forces have killed hundreds of members of the Brotherhood since Mursi was toppled. Thousands have been arrested, including top leaders.

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